Really? 5-7% weight loss guideline is not researched based?

We have taken, as gospel, the guideline of weight loss of greater than 5-7% (7-10% in many circles) as dangerous for newborns and requires supplementation – for years.  Is this an arbitrary line in the sand, or serious research?

What do you mean that the research upon which this guideline is based might be flawed?  That data was incompletely gathered, sample sizes were too small, formula supplemented infants were not excluded or the supplementation was not recorded.  Was the weight loss effect of maternal IV fluids during labor considered?  The recent article in the Journal of Human Lactation Weighing the Facts: A Systematic Review of Expected Patterns of Weight Loss in Full Term Breastfed Infants questions the foundation of these guidelines.  And this is not the first time the data supporting the weight loss guidelines has been challenged.  Noel-Weiss did so in 2008.

The consequences of over-diagnosing excessive weight loss are many.  The mother’s own breastmilk could be expressed and used as a supplement but often that is not considered, and the handy bottle of formula is offered.  Volumes are often excessive.  That formula bottle contains virtually unlimited amounts of supplement, compared to the volumes the baby would be consuming at the breast, if breastfeeding was going well. 

 
Then there is the disruption to the gut flora.  And the sensitization to cow’s milk through the porous newborn gut wall.  Even one bottle can make a difference.

The possible physical sequela are a concern, but the most serious problem with incorrectly identifying an infant as losing too much weight is the damage done to the mother’s breastfeeding intention.  “Well, from the start, I didn’t get this right”.  So, what does it matter if I offer a bottle when the baby cries and I am tired, or I when I go for my OB check-up, and then one when my home is full of guests and I might be embarrassed, and then when I go out for a while with friends, and then, and then….  It starts a slippery slope.   When a mother hears that her baby is losing too much weight she not only questions the adequacy of her breastmilk but of her mothering capacity.   

So, who will do the research, the right way, and get reliable guidelines?  We then can prevent the serious complications of hypernatremic dehydration in a few infants and preserve the breastfeeding relationship during the dip in weight before the mother’s milk comes in, in many infants.  Research methods have improved, more researchers are looking at these issues and we owe it to our breastfeeding babies and mothers to get this right.

Thulier D.  Weighing the Facts: A Systematic Review of Expected Patterns of Weight Loss in Full-Term, Breastfed Infants.  J Hum Lact. 2016 Feb;32(1):28-34.

Noel-Weiss J, Courant G, Woodend AK. Physiological weight loss in the breastfed neonate: a systematic review.  Open Med. 2008;2(4):e99-e110.